Does x86 have an atomic increment preserving the value that was saved?

Question

I found lock inc addr , but it doesn’t save a copy of the stored value around and even read it right after it could arrive in the same stream after a competing write.

The best solution I have found is a load / inc / cas loop.

Answer 1

lock xadd is your friend.

Answer 2

see atomic_impl.h for more primitives and using x86 / x86_64.